Feed circuit for surgical pumps



v F. A. BELLATO FEED CIRCUIT FOR SURGICAL PUMPS Jul 30, 1957 2,800,904

Filed July 12, 1955 INVENTOR .Fhmk A Bellaio BY Jada 5M United StatesPatent FEED CIRCUIT FOR SURGICAL PUMPS Frank A. Bellato, Stockton,Calif., assignor of one-half to Emily G. Whitehead, Los Angeles, Calif.

Application July 12, 1955, Serial No. 521,604

4 Claims. (Cl. 128-214) This invention relates to medical apparatus, andparticularly to apparatus by means of which medicinal liquids of onekind or another are injected into a patient intravenously.

Heretofore, the use of apparatus of this general type has been cloudedby the fact that at times-even though infrequently--air bubbles havepassed into the veins of the patient along with the desired liquid. Suchan occurrence has bad-if not actually fatal-results.

It is therefore the main object of my invention to provide an apparatusor system for injecting a medicinal liquid into the veins of a patientin such a manner that air bubbles, even though initially mingled withthe fluid, will be separated and escape of themselves from the flowingliquid before the latter reaches the injection needle.

Another object is to provide a system for the purpose, which whileutilizing a constant-delivery pump to circulate the liquid from thesource of supply toward the needles, relies on gravity to actuallydeliver the liquid into the veins, regardless of the pressure generatedby the pump.

A further object of the invention is to arrange a portion of the liquidfeeding conduit of the system so that the head of the gravity flow maybe altered to suit the viscosity of the liquid being administered, andwithout altering or affecting the operation of the pump.

A still further object of the invention is to arrange the conduiting ofthe system so that if a stoppage or restriction at the needle shouldoccur, and the desired gravity flow of the liquid into the veins is noteffected, the liquidunder the action of the pump-will be bypassed backto the source of supply and will not be forced into the veins.

An additional object of the invention is to provide a practical andreliable feed circuit for surgical pumps, and one which will beexceedingly effective for the purpose for which it is designed.

These objects are accomplished by means of such structure and relativearrangement of parts as will fully appear by a perusal of the followingspecification and claims.

The figure on the drawing is a mainly diagrammatic View of the improvedfeed circuit for surgical pumps.

Referring now more particularly to the drawing, and to the characters ofreference marked thereon, the improved feed circuit or system comprisesa suitable container 1 for the liquid 2 to be injected; the containerbeing preferably a capped jar mounted in an inverted position and havingan air tube 3 mounted in the jar cap 4 and projecting into the jar so asto terminate above the level of the liquid therein.

A conduit unit 5 extends from cap 4 to a constant delivery pump 6; unit5 including an inverted T-fitting 7 intermediate its ends.

Extending upwardly from the discharge side of the pump is a conduit 8 inthe form of a flexible tube, which tube at its upper end is connected toone leg 9 of an inverted Y-fitting 10. Another flexible tube 11 isconnected to and depends from the other leg 12 of fitting 10, and at itslower end mounts an injection needle 13 of conventional form. Fitting 10is mounted in connection with a supporting panel 14 at a level abovethat of the jar 1 by means of a clamping strap 15 embracing the stem 10aof said fitting and having thumb screws 16 therethrough to the sides ofthe fitting, and each engaging in any one at a time of a row of tappedholes 17 in the panel.

The flexible tube 8 includes a loop portion 8a so as to allow for anydesired vertical adjustment of the fitting 10 relative to the fixed pumpwithout restraint.

Another flexible air-trap tube 18, which includes a fullcircle loop 19to increase its capacity, is connected to and extends between theupwardly projecting stem 10a of fitting 10 and the upwardly projectingstem 7a of fitting 7.

When the circuit or system is set up for operation the liquid willinitially drain from the jar of itself into conduit 5 as far as theintake of the pump (which is in a plane adjacent the lower end of thejar) and into the air tube 18 to a level the same as that of the liquidin the jar 1, as indicated. When the pump 6 is operated, the liquid isforced upwardly in the tube 8 to the top of the leg 9 of fitting 10, orto the point or apex 20 where said leg 9 joins the opposed leg 12 ofsaid fitting. It may be here stated that the pump is controlled, bymeans not here shown, so as to feed a metered amount of the liquid intothe fitting 10 to said apex 20 thereof.

The liquid as being pumped and reaching apex 20 then flows downwardlythrough leg 12 and tube 11 and into the needle 13 by gravity and any airwhich may have been mingled with the liquid as pumped escapes from theliquid through the fitting stem 10 and into tube 18, so that the liquidflowing down through tube 11 is free of air. Such air as enters the tube18 cannot pass into the liquid being drawn to the pump, since the columnof liquid automatically maintained in the lower portion of tube 18, aspreviously described, forms a seal against the flow of air into thepumping line.

Should the needle become clogged so that the liquid will not drain bygravity through the tube 11, the pump if still operatingwill merelyforce the liquid up and into the air-trap tube 18, and ultimately backinto the jar 1, without forcing the liquid into the patient. Any airwhich may be in the tube 18 and forced by the bypassed liquid back intothe jar 1, can of course escape therefrom through the relief tube 3 insaid jar.

The vertical adjustability of the fitting 10 on the supporting panel 14enables the head of the gravity-flowing liquid to be altered accordingto the viscosity of the liquid being administered. In any case, the apex29 of the fitting 10 must always be above the liquid in the jar 1 inorder to avoid the possibility of a siphoning action taking place.

The loop 19, in the air-trap tube 18, provides ample air space in thetube in a compact form, so as to avoid any back pressure being set up inthe tube by the accumulation of air therein.

Although the system, as described above, is especially adapted for usein connection with the giving of intravenous injections, it may also behighly useful to feed various liquids for other medicinal or similarpurposes.

From the foregoing description it will be readily seen that there hasbeen provided such a system as will substantially fulfill the objects ofthe invention, as set forth herein.

While this specification sets forth in detail the present and preferredconstruction of the system, still in practice such deviations therefrommay be resorted to as do not form a departure from the spirit of theinvention, as set forth herein.

Having thus described the invention, the following is V claimed as newand useful and upon which Letters Patent are desired:

1. A-liquid-injection system comprising acontainer for a supply ofliquid, a constant-deliveryfpump, a conduit extending from the bottom ofthe container tojthe intake of the pump, an inverted Y-fitting'securediin a fixed position at a relatively high level, said fittinghaving down! wardly facing legs disposed in diverging relation and anupstanding stem above the legs, aconduit from the discharge of the pumpto one leg of the fitting, a flexible conduit connected to anddependingtfrom the other leg and mounting an injection needle at itslower end for gravity feeding of, the liquid from the Y-fitting to' theneeedle, and an air-trap conduit connected 'at one end to the upstandingstem and at the other end to the first named conduit; the air-trapconduitincluding a portion upstanding from said first named conduit to aheight not less than that of the container. '7 a 2. A system, as inclaim 1, with a support on which the container, pump, and Y-fitting aremounted as a unit, said Y-fitting being disposed at a level above thetop level of the liquid in the container.

3. A system, as in claim 1, with a support on which the container, pump,and Y-fitting are mounted as a unit, and means mounting the Y-fitting onthe support for vertical adjustment thereon. H v

4. A system, as in claim 1, in which the air trap conduit is formedintermediate its ends with a coiled portion to increase the air holdingcapacity of said conduit.

References Cited'in the file of this patent

